Referring to FIG. 1, a conventional electricity architecture includes at least one alternating current (AC) transformer (e.g., two AC transformers 91, 92), at least one generator (e.g., two generators 93, 94), at least one uninterruptible power system (UPS) (e.g., two UPS's 95, 96), a power distribution unit (PDU) 97, an AC power shelf 98, a direct current (DC) bus 99, and a plurality of electronic devices (such as two servers 991, 992 and two storage devices 993, 994). The AC transformer 91, the generator 93 and the UPS 95 are electrically connected to the PDU 97 through a transmission line 10, and similarly, the AC transformer 92, the generator 94 and the UPS 96 are electrically connected to the PDU 97 through another transmission line 20. The PDU 97 is configured to distribute electric power from one of the transmission lines 10, 20 to the AC power shelf 98 such that the servers 991, 992 and the storage devices 993, 994 are powered by the electric power via the AC power shelf 98.
Each of the AC transformers 91, 92 is configured to receive electricity from a power plant or a front-end transformer, and to step down voltage of the electricity so as to output an AC output to the PDU 97 through the corresponding one of the transmission lines 10, 20.
The generators 93, 94 are, for example, diesel generators. Each of the generators 93, 94 is configured to detect voltage value of the AC output from the respective one of the AC transformers 91, 92. When it is detected that the AC output from the respective one of the AC transformers 91, 92 is abnormal (for example, the voltage value is lower than a predetermined value), the generator 93, 94 operates to provide AC electricity to the PDU 97 through the corresponding one of the first and second transmission lines 10, 20.
Each of the UPS's 95, 96 includes an AC-to-DC converter, a power storage module, a DC-to-AC converter and a control unit. The control unit of each UPS 95, 96 is configured to detect voltage value at the corresponding one of the first and second transmission lines 10, 20. The control unit controls the AC-to-DC converter to convert the electric power, which is received from the corresponding one of the first and second transmission lines 10, 20, into DC power, and to store electric energy of the DC power in the power storage module when the voltage value is within a normal range. The control unit controls the DC-to-AC converter to release the energy stored in the power storage module to the corresponding one of the first and second transmission lines 10, 20 when the voltage value is lower than a predetermined voltage value.
Since each of the UPS's 95, 96 includes the AC-to-DC converter and the DC-to-AC converter, the volume of each of the UPS's 95, 96 is relatively large, making installation difficult. In addition, since electric power conversion (AC-to-DC or DC-to-AC) is required both in storing electric energy into the power storage module and in releasing electric energy from the power storage module, efficiency of the energy transformation is relatively low.